<p>TOKYO (Reuters) - In the battle to become the global messaging app of choice, China's WeChat and Japan-based Line have brought out some large marketing guns - TV ads featuring soccer star Lionel Messi, for instance - that have powered promising bursts of overseas growth.</p><p>The big bucks strategy stands in stark contrast to other messaging apps, or even apps in general, which spend little on marketing. U.S. rival WhatsApp eschews advertising altogether and has instead relied on word of mouth to become the dominant chat app in many Western countries.</p><p>WeChat, a unit of Tencent Holdings Ltd, has budgeted up to $200 million for marketing overseas this year including the Messi ads. Line, owned by Korean company Naver Corp, declines to say how much it spends but has relied heavily on celebrities in TV ads in many markets.</p><p>Spurring them on is the belief that now is their chance to build an international brand, and that if they play their cards right, they can become serious threats to more established social networks such as Facebook Inc and its instant messaging service.</p><p><a href="http://www.reuters.com/article/2013/10/22/net-us-asia-messaging-idUSBRE99L1CZ20131022">Keep reading...</a></p>